/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __6LOWPAN_NHC_H #define __6LOWPAN_NHC_H #include <linux/skbuff.h> #include <linux/rbtree.h> #include <linux/module.h> #include <net/6lowpan.h> #include <net/ipv6.h> /** * LOWPAN_NHC - helper macro to generate nh id fields and lowpan_nhc struct * * @__nhc: variable name of the lowpan_nhc struct. * @_name: const char * of common header compression name. * @_nexthdr: ipv6 nexthdr field for the header compression. * @_nexthdrlen: ipv6 nexthdr len for the reserved space. * @_idsetup: callback to setup id and mask values. * @_idlen: len for the next header id and mask, should be always the same. * @_uncompress: callback for uncompression call. * @_compress: callback for compression call. */ #define LOWPAN_NHC(__nhc, _name, _nexthdr, \ _hdrlen, _idsetup, _idlen, \ _uncompress, _compress) \ static u8 __nhc##_val[_idlen]; \ static u8 __nhc##_mask[_idlen]; \ static struct lowpan_nhc __nhc = { \ .name = _name, \ .nexthdr = _nexthdr, \ .nexthdrlen = _hdrlen, \ .id = __nhc##_val, \ .idmask = __nhc##_mask, \ .idlen = _idlen, \ .idsetup = _idsetup, \ .uncompress = _uncompress, \ .compress = _compress, \ } #define module_lowpan_nhc(__nhc) \ static int __init __nhc##_init(void) \ { \ return lowpan_nhc_add(&(__nhc)); \ } \ module_init(__nhc##_init); \ static void __exit __nhc##_exit(void) \ { \ lowpan_nhc_del(&(__nhc)); \ } \ module_exit(__nhc##_exit); /** * struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation * * @node: holder for the rbtree. * @name: name of the specific next header compression * @nexthdr: next header value of the protocol which should be compressed. * @nexthdrlen: ipv6 nexthdr len for the reserved space. * @id: array for nhc id. Note this need to be in network byteorder. * @mask: array for nhc id mask. Note this need to be in network byteorder. * @len: the length of the next header id and mask. * @setup: callback to setup fill the next header id value and mask. * @compress: callback to do the header compression. * @uncompress: callback to do the header uncompression. */ struct lowpan_nhc { struct rb_node node; const char *name; const u8 nexthdr; const size_t nexthdrlen; u8 *id; u8 *idmask; const size_t idlen; void (*idsetup)(struct lowpan_nhc *nhc); int (*uncompress)(struct sk_buff *skb, size_t needed); int (*compress)(struct sk_buff *skb, u8 **hc_ptr); }; /** * lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr. * * @nexthdr: ipv6 nexthdr value. */ struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr); /** * lowpan_nhc_check_compression - checks if we support compression format. If * we support the nhc by nexthdr field, the function will return 0. If we * don't support the nhc by nexthdr this function will return -ENOENT. * * @skb: skb of 6LoWPAN header to read nhc and replace header. * @hdr: ipv6hdr to check the nexthdr value * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of * replaced header. */ int lowpan_nhc_check_compression(struct sk_buff *skb, const struct ipv6hdr *hdr, u8 **hc_ptr); /** * lowpan_nhc_do_compression - calling compress callback for nhc * * @skb: skb of 6LoWPAN header to read nhc and replace header. * @hdr: ipv6hdr to set the nexthdr value * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of * replaced header. */ int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr, u8 **hc_ptr); /** * lowpan_nhc_do_uncompression - calling uncompress callback for nhc * * @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions. * @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value. * @dev: netdevice for print logging information. * @hdr: ipv6hdr for setting nexthdr value. */ int lowpan_nhc_do_uncompression(struct sk_buff *skb, const struct net_device *dev, struct ipv6hdr *hdr); /** * lowpan_nhc_add - register a next header compression to framework * * @nhc: nhc which should be add. */ int lowpan_nhc_add(struct lowpan_nhc *nhc); /** * lowpan_nhc_del - delete a next header compression from framework * * @nhc: nhc which should be delete. */ void lowpan_nhc_del(struct lowpan_nhc *nhc); /** * lowpan_nhc_init - adding all default nhcs */ void lowpan_nhc_init(void); #endif /* __6LOWPAN_NHC_H */